PCI: cpqphp: Remove unnecessary null test before debugfs_remove()

Fix checkpatch warning:
"WARNING: debugfs_remove(NULL) is safe this check is probably not required"

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: Ryan Desfosses <ryan@desfo.org>